In a cohort of asbestos mine workers, 150 deaths from lung cancer are observed over 20 years. Based on age and sex specific national mortality rates applied to the cohort, 100 such deaths were expected. The Standardized Mortality Ratio (SMR) is:
- A 67
- B 100
- C 150 ✓
- D 250
Correct answer: C. 150
Explanation
SMR is calculated as observed deaths divided by expected deaths, multiplied by 100: (150 / 100) x 100 = 150. An SMR of 150 indicates a 50 percent excess mortality from lung cancer compared with the general population. Option A inverts the ratio, option B implies no excess, and option D would require observed deaths four times the expected figure. SMR is the standard summary measure in occupational cohort studies.
Reference: Park's Textbook of Preventive and Social Medicine, 27th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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